The Android operating system is a Linux-based open-source operating system that is mainly used in portable devices. In 2005, Google acquired, invested and established the Open Handset Alliance to develop and improve the Android system so as to gradually extend it to tablet PCs and other fields. Main competitors of the Android operating system are Apple's iOS system and RIM's Blackberry OS system. In the first quarter of the year 2011, the Android operating system, for the first time, exceeded the Symbian system in the global market share to be the world number one. The data from February 2012 show that the Android operating system accounted for 59% of the global smartphone operating system market, and 68.4% in China.
Mobile phones using the Android operating system usually come with at least one Secure Digital Memory Card (referred to as an SD card for short), and when a user disconnects an SD card from a mobile phone (that is, the SD card is unmounted), then connects the SD card to a computer so as to copy data from the computer to the SD card, and then inserts the SD card back into the mobile phone (that is, the SD card is mounted), it usually requires the user to use another auxiliary software tool to find the files that are just imported by the SD card into the mobile phone, and those files cannot be quickly located.